e300v2 Documentation

CAD Audio e300v2

Multi-Pattern Condenser Microphone

The current shipping version, the e3002, is a second-generation design manufactured to CAD’s specs overseas. The original e300 was manufactured in the US and had slightly different specifications, such as the HPF (which moved from 80Hz to 135Hz). There are likely other changes we have not identified.

The mic can be powered by either phantom power or by two 9V batteries. Unusually, phantom power is not used to drive the microphone’s amplifier circuit directly; rather, it charges two built-in rechargeable batteries, which are capable of driving the high current needs of the output circuit’s opamps during high-SPL transients.

The capsule is a large-diaphragm true condenser, presumably a K67 style. According to measurements submitted by an E300S owner, the capsule’s outside diameter is 33.6mm; the suspended area of the diaphragm has a diameter of 26.3mm.

CAD

Equitek microphones … do not use any discrete FETs. Instead, [they] use advanced high speed OpAmps (Operational Amplifiers). These OpAmps are individually laser trimmed for optimum performance and have very high gain. This allows a large amount of negative feedback to be used to significantly reduce any non-linearity. During transients, these OpAmps may require more current than typical phantom power supplies can deliver. The extra current demands are accommodated by our unique power supply design. Instead of using phantom power to operate the microphone, we use it to charge a pair of rechargeable batteries. This system creates a huge current reserve for the microphone’s electronics, yet there is no maintenance involved because the microphone automatically keeps the batteries charged during use.

According to CAD, the impedance conversion circuitry is linear with respect to frequency response; there is no fixed EQ within the circuitry.

Switches on the front of the microphone body provide power cutoff (for optional 9V batteries), a high-pass filter (135Hz), a -20dB pad, and pattern selection: cardioid, figure-of-8, or omnidirectional.

Electronic Musician, 2006…the CAD Equitek e300-2 always sounded overly bright to me, and often strangely filtered in cardioid mode. The omni pattern delivered even less low end, more exaggerated highs around 10 kHz, and significantly lower gain. I was surprised to find that the mic’s figure-8 pattern offered the best fidelity. In this pattern, the e300-2 came close to the fairly neutral sound of the C 414 B-XLS’s cardioid pattern, with a rounder low end and smoother highs.